I have this problem
An investor enters into an agreement to contribute $7,000$ immediately and $1,000$ at the end of two years in exchange for the receipt of $4,000$ at the end of one year and $5,500$ at the end of three years.
I tried setting up this problem by equating each of their present values: $$7000+1000v^2 = 4000v + 5500v^3 \hspace{.3in} [1]$$ Notice that equation $[1]$ can be set up in two different ways: $$NPV_2(i) = 7000+1000v^2-4000v-5500v^3=0 \hspace{.3in} [2]$$ $$NPV_3(i) = 4000v+5500v^3-7000-1000v^2 = 0 \hspace{.3in} [3]$$
And if I evaluate equation $[2]$ at $i=0.09$ I get $NPV_2(0.09)= -75.05$
while using euation $[3]$ at $i=0.09$ yields $NPV_3(0.09) = 75.05$
Why are they different?